#include <opencv2/opencv.hpp>
#include <iostream>
#include <math.h>

using namespace std;
using namespace cv;

namespace chapter030 {

	Mat src, dst;
	const char* output_win = "findcontours-demo";
	int threshold_value = 100;
	int threshold_max = 255;
	RNG rng;
	void Demo_Contours(int, void*);
	int chapter030(int argc, char** argv) {
		src = imread("D:/vcprojects/images/happyfish.png");
		if (src.empty()) {
			printf("could not load image...\n");
			return -1;
		}
		namedWindow("input-image", CV_WINDOW_AUTOSIZE);
		namedWindow(output_win, CV_WINDOW_AUTOSIZE);
		imshow("input-image", src);
		cvtColor(src, src, CV_BGR2GRAY);

		const char* trackbar_title = "Threshold Value:";
		createTrackbar(trackbar_title, output_win, &threshold_value, threshold_max, Demo_Contours);
		Demo_Contours(0, 0);

		waitKey(0);
		return 0;
	}

	void Demo_Contours(int, void*) {
		Mat canny_output;
		vector<vector<Point>> contours;
		vector<Vec4i> hierachy;
		Canny(src, canny_output, threshold_value, threshold_value * 2, 3, false);
		findContours(canny_output, contours, hierachy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));

		dst = Mat::zeros(src.size(), CV_8UC3);
		RNG rng(12345);
		for (size_t i = 0; i < contours.size(); i++) {
			Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
			drawContours(dst, contours, i, color, 2, 8, hierachy, 0, Point(0, 0));
		}
		imshow(output_win, dst);
	}
}